Continuous tokamak operation and non inductive current drive methods

Abstract

In order to maintain the number of discharges of a tokamak fusion reactor below the critical limit during its estimated lifetime, the plasma burn time must be of the order of one day. The efficiencies of the two most promising active current drive methods, LHCD and NBCD, are considered. Two projects of continuous reactors based on purely passive current drive methods (bootstrap effect and synchrotron radiation) are presented. Although no external power is then required to drive the current, additional heating for ignition and current ramp up may be required. The difficulties associated with the use of active current drive are compared to those due to discontinuous reactor operation.